Is there a website that you can look up the topographic info on lakes? I'd like to see where the deep places and ledges might be on the lake I am currently fishing on.

Navionics.com

the web-based version is free the phone app is not 

try avionics or just a google search

 

University of Florida has free topo maps on all the major lakes in the state of Florida.  Try your University web sites and see if your system has done the same for you.  I print them and then have them laminated.  With the right marker pen I can make notes right on the map.  It is a great resource, and the best part is its free.

click on tools at top of page then clip on interactive lake map.